[Docs] Versionize documentation

[lorensr]

Relevant both for docs and API reference. And latest version of API ref could be deployed from release branch instead of main so that it's not ahead of what's published on npm.

[bergundy]

Yes please

[cretz]

Tangentially related (feel free to ignore) - a high-level set of release notes may also be reasonable (I know there's a lower-level CHANGELOG.md). Or if we start using GH "releases" instead of just tags, that is a place they could be stored too.

[bergundy]

We add high level release notes to CHANGLOG.md.
We might want to do GH releases, I know lerna support that.

[lorensr]

Current alternative is to build and view locally:

git clone https://github.com/temporalio/sdk-typescript.git
cd sdk-typescript
git checkout v0.16.4
git submodule update --init --recursive
npm ci
npm run build
cd packages/docs
npm start